Co-production of phenol, acetone, alpha-methylstyrene and propylene oxide, and catalyst therefor

ABSTRACT

A process is disclosed for producing α-methylstyrene, acetone, and phenol wherein the amount of α-methylstyrene produced may be controlled by selectively converting a portion of the cumene hydroperoxide to dimethyl phenyl carbinol, the hydrated form of α-methylstyrene. The dimethyl phenyl carbinol thus produced will lead to increased production of α-methylstyrene upon dehydration in the acid cleavage unit of the phenol plant. By controlling the fraction of the cumene hydroperoxide reduced to dimethyl phenyl carbinol, the amount of α-methylstyrene produced in the plant can be continuously set to meet the demand of the market for α-methylstyrene. Also disclosed is a non-acidic catalyst for reduction of cumene hydroperoxide.

FIELD OF THE INVENTION

[0001] This invention relates to the co-production of phenol, acetone,α-methylstyrene and optionally, propylene oxide, and catalyst therefor;more particularly to a process and catalyst for producing phenol,acetone and α-methylstyrene from cumene hydroperoxide.

BACKGROUND OF THE INVENTION

[0002] Increased amounts of α-methylstyrene (AMS) may be produced in acombined phenol and acetone plant by selectively reducing cumenehydroperoxide (CHP) to dimethyl phenyl carbinol (DMPC), the hydratedform of AMS. DMPC is also known as 2-phenyl-2-propanol or dimethylbenzylalcohol (DMBA). As a byproduct of the oxidation of cumene to CHP, smallamounts of DMPC are produced. The DMPC undergoes dehydration in thepresence of an acid catalyst to yield AMS. Some phenol manufacturersrecover the AMS if it is produced in sufficient quantities. Other phenolmanufacturers do not recover AMS, but hydrogenate it back to cumene forrecycle to the oxidation reactor. The hydrogenation of the AMS may takeplace after recovery of an AMS/cumene stream in the distillation sectionof the phenol plant. As an alternative approach, the entire cleavagereactor effluent, including all of the AMS may be hydrogenated prior toseparation of the phenol and acetone in the distillation section of theplant, e.g., U.S. Pat. No. 5,245,090.

[0003] AMS is used industrially in a variety of applications,particularly in the production of certain copolymers and specialtypolymers. In addition, AMS finds utility as an intermediate in theproduction of fine chemicals such as unsaturated AMS dimers. Thesedimers are used as molecular weight controlling agents in the productionof copolymers, such as acrylonitrile-butadiene-styrene resins andstyrene-butadiene rubber. The hydrogenated forms of AMS dimers are ofindustrial value as components in lubrication compositions.

[0004] A number of patented processes have been developed in an attemptto increase the AMS yield in the production of phenol from cumene. Theseprocesses typically seek to increase the AMS yield by minimizing theloss of AMS through secondary reactions. One approach employs amulti-step process that reacts CHP and DMPC with sulfuric acid in a backmixing reactor to produce dicumyl peroxide that subsequently undergoesdecomposition at elevated temperature under plug-flow conditions toproduce AMS, phenol, and acetone e.g., U.S. Pat. No. 4,358,618. Analternative approach to minimize the loss of AMS through secondaryreactions employs a multi-step process that decomposes the CHP in a backmixing reactor followed by dehydration of the DMPC in a plug-flowreactor after an inhibitor such as acetone and/or water has been addedto control secondary reactions of AMS, e.g., U.S. Pat. Nos. 5,998,677and 5,463,136. These processes, however, do not increase the yield ofAMS over the theoretical maximum that can be obtained by fulldehydration of the DMPC produced in the oxidizer unit. These processesmerely seek to minimize the loss of AMS to heavy byproducts, and resultin AMS yields of 70-80% of the theoretical maximum based on the DMPCexiting the oxidizer unit.

[0005] The process of this invention provides a method for increasingthe AMS yield above the theoretical maximum based on the DMPC in theoxidizer effluent by reducing a portion of the CHP stream to DMPC over asuitable heterogeneous catalyst. This process stream, having elevatedamounts of DMPC, can then be fed to the cleavage unit of a phenol plantwhere the remaining CHP undergoes acid-catalyzed decomposition to phenoland acetone. During the decomposition, the acid catalyst dehydrates theDMPC to AMS. By controlling the fraction of the CHP reduced to DMPC, theamount of AMS produced in the plant can be continuously set to meet thedemand of the market.

[0006] The process of this invention also provides a method forcontrolling the AMS yield by reacting a portion of the CHP with anexogenous source of propylene in an epoxidation reaction. In theepoxidation reactor, a portion of the CHP is reduced in the presence ofan epoxidation catalyst to DMPC with propylene going to propylene oxide.The propylene oxide can be recovered as a valuable byproduct. The liquidsolution leaving the epoxidation reactor has elevated amounts of DMPC,and can then be fed to the cleavage unit of a phenol plant where theremaining CHP undergoes acid-catalyzed decomposition to phenol andacetone. During the decomposition, the acid catalyst can dehydrate DMPCto AMS. By controlling the fraction of the CHP reduced to DMPC, theamount of AMS produced in the plant can be continuously set to meet thedemand of the market for AMS.

[0007] No process currently exists that allows a phenol manufacturer tomake on-demand AMS. AMS may only be recovered from dehydration of DMPCproduced in the oxidation reactor. Current processes do not allowflexibility in controlling the amount of DMPC produced via oxidation asunfavorable side reactions lead to higher quantities of acetophenonewhen DMPC levels are increased by oxidation. Numerous methods have beendisclosed in the patent literature to maximize the yield of AMS,regardless of whether AMS is recovered as a separate product orhydrogenated to cumene and recycled. These methods for improving the AMSyield seek to minimize side reactions of the AMS by using acetone as asolvent to dilute the AMS or using alternative reactor configurations.Regardless of the method used, the maximum AMS yield for currentstate-of-the-art plants is typically within the range of 70-80% based onthe DMPC leaving the oxidation reactor.

SUMMARY OF THE INVENTION

[0008] This invention includes a process for co-producing AMS along withacetone and phenol which comprises the steps of oxidizing a streamcontaining cumene in the presence of an oxygen-containing stream to forma stream containing CHP. A portion of the CHP stream may be reduced inthe presence of a catalyst, preferably a non-acidic catalyst to form astream containing DMPC. The DMPC-containing stream and the remainingportion of said CHP stream are converted in the presence of a catalyst,preferably an acidic catalyst to form a product stream containing AMS,acetone, and phenol. AMS, acetone, and phenol are each separated fromsaid product stream. In this invention, the amount of CHP reduced toDMPC may be varied from about zero up to about 50 weight percent of thestream containing CHP.

[0009] This invention also includes a process for co-producing AMS andpropylene oxide along with acetone and phenol which comprises the stepsof oxidizing a stream containing cumene in the presence of anoxygen-containing stream to form a stream containing CHP. A portion ofthe CHP stream may be reduced in the presence of an epoxidation catalystand a propylene-containing stream to form a stream containing DMPC andpropylene oxide. Propylene oxide is separated from the reaction streamleaving a stream containing DMPC. The DMPC-containing stream and theremaining portion of said CHP stream are converted in the presence of acatalyst, preferably an acidic catalyst, to form a product streamcontaining AMS, acetone, and phenol. AMS, acetone, and phenol are eachseparated from said product stream. In this invention, the amount of CHPreduced to DMPC may be varied from about zero up to about 50 weightpercent of the stream containing CHP.

[0010] This invention further includes a non-acidic catalyst forreduction of cumene hydroperoxide to dimethyl phenyl carbinol, saidcatalyst contains a metal and a catalyst support, preferably cobaltsupported on zirconium oxide or on aluminophosphates.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is a schematic flow diagram of a processing scheme for theco-production of phenol, acetone, and AMS.

[0012]FIG. 2 is a schematic flow diagram of a processing scheme for theco-production of phenol, acetone, AMS, and propylene oxide.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0013]FIG. 1 represents a schematic flow diagram of an embodiment ofthis invention as processing scheme 1 for the co-production of phenol,acetone, and AMS. Cumene in stream 10 is fed to an oxidation reactor 101where CHP is produced by reaction of the cumene with oxygen from the airfed as stream 12. Initiators to facilitate the oxidation of the cumenemay be added as stream 13. Preferably, these initiators may be anorganic hydroperoxide, such as CHP, tert-butyl hydroperoxide,ethylbenzene hydroperoxide or the like. Alternatively, these initiatorsmay be azo type free radical initiators or peroxy type free radicalinitiators that are known to catalyze the oxidation of organichydrocarbons. Examples of such azo type free radical initiators andperoxy type free radical initiators that may be used in the process ofthe invention are described in Encyclopedia of Polymer Science andEngineering, Volume 2, Page 143 et seq., 1985, and Volume 11, Page 1 etseq., 1988, respectively. The CHP stream 14, containing DMPC andacetophenone, together with unreacted cumene may be concentrated byremoving a portion of the unreacted cumene prior to the cleavage sectionof processing scheme 1 (not shown).

[0014] In an embodiment of this invention where increased amounts of AMSare produced together with phenol and acetone, the CHP stream 14 is thensplit into streams 15 and 16, with the split ratio α=16/15 set accordingto desired plant output of AMS. Stream 16 is fed to the reductionreactor 103 where a portion of the CHP in stream 16 is reduced to DMPCover a suitable catalyst. Stream 17 leaving the reduction reactor has anincreased concentration of DMPC relative to CHP stream 14. Preferably,in order to minimize the conversion of CHP to phenol and acetone inreduction reactor 103, the catalyst used therein may be a heterogeneouscatalyst comprised of a non-acidic or low acidity catalyst support and ametal. Non-acidic or low acidity catalyst supports include, but are notlimited to, silica, alumina, crystalline or amorphous aluminophosphates;Group 4 metal oxides, such as titania, zirconia, hafnia, and mixturesthereof; and mesoporous molecular sieves exemplified by MCM-41. Themetal deposited on such catalyst supports includes, but is not limitedto, a Group 8, Group 9, or Group 10 transition metal, such as cobalt,iron, nickel, or mixtures thereof; a Group 2 metal, such as magnesium,calcium, barium, or mixtures thereof; a Group 1 metal, such as lithium,sodium, cesium, and mixtures thereof; a Group 3 metal, such as scandium,yttrium, lanthanum, or mixtures thereof; or mixtures and/or combinationsof the above. Group numbers used in this patent application are from thePeriodic Table of the Elements using the IUPAC format described in theCRC Handbook Chemistry and Physics, 79th Edition, CRC Press, Boca Raton,Fla. (1998).

[0015] More preferably, such heterogeneous catalysts may be a Group 8,Group 9 or Group 10 transition metal on a support, such as cobaltsupported on a Group 4 metal oxide, such as zirconium oxide, or cobaltsupported on aluminophosphate, as disclosed in Examples 1 and 3,discussed below. These mixed metal oxides can be prepared by typicalmethods known to those skilled in the art such as impregnation,incipient wetness or ion exchange, or they can be prepared byco-precipitation of the metal oxides from soluble salt solutions.

[0016] Streams 15 and 17 are fed to first cleavage reactor 102 where anacidic catalyst decomposes the CHP into phenol and acetone, anddehydrates the DMPC into AMS. The acidic catalyst may be in the liquidphase, such as sulfuric acid, fed via stream 18. Preferably, thecatalyst may be in the solid phase, such as a solid acid catalyst,capable of decomposing hydroperoxides into alcohols and ketones. Suchsolid acid catalysts include catalysts produced by calcining a source ofa Group 4 metal oxide with a source of an oxyanion of a Group 6 metal ata temperature of at least 400° C., as disclosed in U.S. Pat. No.6,169,215; sulfated transition metal oxides, as disclosed in U.S. Pat.No. 6,169,216; and a mixed metal oxide of cerium and a Group 4 metal, asdisclosed in U.S. Pat. No. 6,297,406. The disclosures of U.S. Pat. Nos.6,169,215; 6,169,216; and 6,297,406; are fully incorporated herein byreference. The effluent from first cleavage reactor 102, stream 19, iscomposed of phenol, acetone, AMS, acetophenone, cumene, and some heaviesproduced from secondary reactions.

[0017] To minimize the formation of heavies in any of the embodimentsdescribed herein, it is preferable to dilute the AMS in the cleavagereactor. One possible diluting stream is the product itself. If firstcleavage reactor 102 is operated with a solid acid catalyst, such asthose described in U.S. Pat. Nos. 6,169,215; 6,169,216; and 6,297,406,in a plug flow reactor configuration, it is desirable to have as low aspossible an AMS concentration at the inlet to minimize secondaryreactions of the AMS. To achieve this goal, it is desirable to minimizethe AMS in the diluting stream 23. This may be achieved by hydrogenatinga portion of the effluent stream 19 as stream 20. Stream 20 ishydrogenated in hydrogenation reactor 104 in the presence of hydrogenstream 22 and a hydrogenation catalyst (not shown).

[0018] Preferably, the hydrogenation catalyst for use in thehydrogenation reactor 104 includes a hydrogenation component and acatalyst support. The hydrogenation component of the hydrogenationcatalyst may be derived from a Group 8, Group 9, or Group 10 transitionmetal, such as platinum, iridium, osmium, palladium, rhodium, ruthenium,nickel, cobalt, iron, and mixtures of two or more thereof. Preferredmetals are palladium and platinum. A Group 8, Group 9 or Group 10transition metal may optionally be mixed with a Group 14 metals,preferably tin, and/or a Group 7 metal, preferably rhenium andmanganese. Other metals known in the art capable of acting as ahydrogenation component include, but are not limited to, a Group 6metal, such as tungsten, and molybdenum; a Group 11 metal, such ascopper, silver, and gold, either alone, or in combination. The amount ofthe hydrogenation component may be in the range of 0.001 to 30 wt.% ofthe total catalyst, preferably from 0.01 to 5 wt.%. The hydrogenationcomponent can be exchanged onto the support material, impregnated intoit or physically admixed with it. Suitable catalyst support materialsare those well known in the art, for example, alumina, silica, clay,carbon, zirconia, titania, and mesoporous molecular sieves, asexemplified by MCM-41 type materials and mixtures thereof.

[0019] The diluting stream 23 may be fed completely into the front endof first cleavage reactor 102. Alternatively, the diluting stream 23 maybe fed in one or more stages down the length of the bed to provide thenecessary diluting effect. The split ratio β=20/21 is set to provide thenecessary diluent to minimize the formation of heavy components.Increasing β reduces the amount of heavy components produced in thecleavage reactor(s), but does so at the cost of a loss of recoverableAMS. In addition to providing the necessary dilution to the cleavagereactor, stream 23 may be cooled prior to entering first cleavagereactor 102 to assist in heat removal from the reactor. As analternative diluent, or in addition to the product recycle, acetone fromthe acetone tower 113 may be returned to the cleavage reactor in stream29.

[0020] Stream 21 from the first cleavage reactor 102 may be sent to asecond cleavage reactor 105. Second cleavage reactor 105 may be operatedat conditions that are the same or are different than those in firstcleavage reactor 102. For example, second cleavage reactor 105 may beoperated at a higher temperature than first cleavage reactor 102. Secondcleavage reactor 105 would typically be a plug-flow reactor, and may, ormay not contain a catalyst bed. If a liquid acid such as sulfuric acidis used in first cleavage reactor 102, there may be sufficient acidityremaining in stream 21 to catalyze the necessary reactions in secondcleavage reactor 105. In a preferred embodiment, second cleavage reactor105 contains a solid acidic catalyst, such as those described in U.S.Pat. Nos. 6,169,215; 6,169,216; and 6,297,406. Second cleavage reactor105 is used to decompose any dicumyl peroxide that may form in firstcleavage reactor 102, and convert any residual CHP to phenol andacetone. In an alternative embodiment, a series of two or more reactorsmay be used for final conversion of the CHP, and a diluent such asacetone may or may not be added before each reactor bed.

[0021] In an alternate embodiment of this invention, processing scheme 1may be operated to produce phenol and acetone with minimal amounts ofAMS produced. When operating in this mode, the split ratio α is zerowherein all of CHP stream 14 is fed to first cleavage reactor 102 (asstream 15), thereby bypassing reduction reactor 103. Diluent stream 23,and optionally stream 29, along with stream 15 are then fed to firstcleavage reactor 102 in the presence of an acidic catalyst wherein CHPis decomposed to phenol and acetone. Such acidic catalyst is preferablya solid acid catalyst that is capable of decomposing hydroperoxides,such as those disclosed above. Effluent stream 19 in this embodiment iscomprised mainly of phenol, acetone, cumene, and small amounts of AMSand heavies. Diluent stream 23 is formed by hydrogenating stream 20, aportion of effluent stream 19, in hydrogenation reactor 104 using asuitable hydrogenation catalyst, such as those disclosed above. Stream21, the remaining portion of effluent stream 19, may then be fed to asecondary cleavage reactor 105 for further conversion, if desired.

[0022] In still another embodiment of this invention, a two-bed, singlereactor may be used (not shown) for reduction and cleavage since thereaction temperatures for DMPC formation and CHP cleavage are similar. Atop bed may contain a heterogeneous catalyst that does not convertsignificant amounts of CHP to phenol and acetone, as discussed above, toproduce DMPC to give the desired AMS yield. The bottom bed may contain asuitable acidic catalyst to decompose the remaining CHP to phenol andacetone and dehydrate the DMPC to AMS.

[0023] While it is preferable to use a solid catalyst in cleavagereactors 102 and 105, as discussed above, it is within the scope of thisinvention to utilize liquid acids, such as sulfuric acid, to accomplishthe decomposition of the CHP (not shown). If use is made of liquidacids, a neutralization step would be required prior to the recoverysection of the plant. Such a neutralization step may employ liquid basesor ion exchange resins or the like, as is well known to those skilled inthe art.

[0024] There are many ways known to those skilled in the art to separatethe individual components from stream 24 exiting the cleavage section ofthe plant. The following distillation scheme is presented forillustrative purposes only. Stream 24 from cleavage reactor 105 is sentto the Crude Acetone Tower 110 where acetone and the lighter componentsare separated from phenol and the heavier components. The overheadstream 25 is sent to the Lights Topping Tower 112 where light compoundssuch as acetaldehyde are removed as stream 26. The bottoms from thetopping tower, stream 27 are fed to the Refined Acetone Column 113,where product specification acetone is recovered as stream 28. Thebottoms from the Crude Acetone Tower 110, stream 31, comprising phenol,and some AMS, cumene, acetophenone and heavies, are fed to the HeavyEnds Tower 114, where the heavy components are separated as stream 33.The overhead stream 32 is fed to the Hydrocarbon Removal Tower 115,where the residual AMS and cumene are separated from the phenol and passto the AMS recovery section as stream 34. The crude phenol product,stream 35, is fed to the Phenol Finishing Tower 116, where productspecification phenol is recovered overhead as stream 36. The AMS andcumene streams 30 and 34 are fed to the AMS Recovery Tower 117 where AMSis recovered as product stream 39, while cumene as stream 38 is returnedto the oxidizer reactor 101.

[0025] By controlling the split ratios α and β, the amount of AMSproduced in the plant can be continuously set, from about zero to about50 wt.% of the stream containing CHP; preferably from about zero toabout 30 wt.% of the stream containing CHP; more preferably from aboutzero to about 20 wt.% of the stream containing CHP; and most preferablyfrom about zero to about 15 wt.% of the stream containing CHP, to meetthe demand of the market for AMS.

[0026]FIG. 2 represents a schematic flow diagram of still anotherembodiment of this invention as processing scheme 40 for theco-production of propylene oxide, AMS, phenol, and acetone. Cumene instream 41 is fed to an oxidation reactor 101 where CHP is produced byreaction of the cumene with oxygen from the air fed as stream 42.Initiators to facilitate the oxidation of the cumene may be added asstream 43. Preferably, these initiators may be an organic hydroperoxidesuch as CHP, tert-butyl hydroperoxide, ethylbenzene hydroperoxide or thelike. Alternatively, these initiators may be free radical initiatorsknown to catalyze the oxidation of organic hydrocarbons such as the azotype free radical initiators or any of the peroxy type free radicalinitiators or the like, as disclosed above with respect to processingscheme 1. The CHP stream 45, containing DMPC and acetophenone, togetherwith unreacted cumene may be concentrated by removing a portion of theunreacted cumene prior to the cleavage section of the processing scheme40.

[0027] The CHP stream 45 is then split into streams 46 and 47, with thesplit ratio α=47/46 set according to desired plant output of AMS. Stream47 is fed to the epoxidation reactor 120 where a portion of the CHP instream 47 reacts with a propylene-containing feed stream 44 to producepropylene oxide as a product stream 70. During the epoxidation reaction,CHP is reduced to DMPC over a suitable epoxidation catalyst, whichinclude titanium supported on silica or molybdenum. Preferably, suchepoxidation catalysts may be the catalysts disclosed in U.S. Pat. No.6,114,551, incorporated herein by reference. Stream 48 leaving thereduction reactor, therefore, has an increased concentration of DMPCrelative to CHP stream 45. Streams 48 and 46 are fed to first cleavagereactor 102 where an acidic catalyst decomposes the CHP into phenol andacetone, and dehydrates the DMPC into AMS. Preferably, suitable acidiccatalysts, such as a mixed metal oxide, are the same as those disclosedabove with respect to processing scheme 1. The effluent from firstcleavage reactor 102 is comprised mainly of phenol, acetone, AMS,acetophenone, cumene, and some heavies produced from secondaryreactions.

[0028] To minimize the formation of heavies, it is preferable to dilutethe AMS in the cleavage reactor. One possible diluting stream is theproduct itself. If first cleavage reactor 102 is operated with an acidiccatalyst in a plug flow reactor configuration, it is desirable to haveas low as possible an AMS concentration at the inlet to minimizesecondary reactions of the AMS. To achieve this goal, it is desirable tominimize the AMS in the diluting stream 53. This may be achieved byhydrogenating a portion of the effluent stream 49 as stream 50. Stream50 is hydrogenated in hydrogenation reactor 104, in the presence ofhydrogen fed stream 52 and a hydrogenation catalyst (not shown).

[0029] Suitable catalysts for use in the hydrogenation reactor 104include noble metals such as palladium and platinum supported on asupport that may, or may not, be acidic as disclosed above. The dilutingstream 53 may be fed completely into the front end of the hydrogentationreactor 104. Alternatively, the diluting stream 53 may be fed in one ormore stages down the length of the bed to provide the necessary dilutingeffect. The split ratio β=50/51 is set to provide the necessary diluentto minimize the formation of heavy components. Increasing β reduces theamount of heavy components produced in the cleavage reactor(s), but doesso at the cost of a loss of recoverable AMS. As an alternative diluent,or in addition to the product recycle, acetone from the acetone tower113 may be returned to the cleavage reactor in stream 59.

[0030] Stream 51 from the first cleavage reactor 102 may be sent to asecond cleavage reactor 105. Second cleavage reactor 105 may be operatedat conditions that are the same or are different than those in firstcleavage reactor 102. For example, second cleavage reactor 105 may beoperated at a higher temperature than first cleavage reactor 102.Cleavage reactor 105 would typically be a plug-flow reactor, and may, ormay not contain a catalyst bed. If a liquid acid such as sulfuric acidis used in reactor 102, there may be sufficient acidity remaining instream 51 to catalyze the necessary reactions in reactor 105. In apreferred embodiment, cleavage reactor 105 contains a solid acidcatalyst, such as those described in U.S. Pat. Nos. 6,169,215;6,169,216; and 6,297,406. Cleavage reactor 105 is used to decompose anydicumyl peroxide that may form in first reactor 102, and convert anyresidual CHP to phenol and acetone. In an alternative embodiment, aseries of two or more reactors may be used for final conversion of theCHP, and a diluent such as acetone may or may not be added before eachreactor bed.

[0031] While it is preferable to use a solid catalyst in cleavagereactors 102 and 105 as discussed above, it is within the scope of thisinvention to utilize liquid acids such as sulfuric acid to accomplishthe decomposition of the CHP. If use is made of liquid acids, aneutralization step would be required prior to the recovery section ofthe plant (not shown). Such a neutralization step may employ liquidbases or ion exchange resins or the like, as is well known to thoseskilled in the art.

[0032] There are many ways known to those skilled in the art to separatethe individual components from stream 54 exiting the cleavage section ofthe plant. The following distillation scheme is presented forillustrative purposes only. Stream 54 from the cleavage reactor is sentto the Crude Acetone Tower 110 where acetone and the lighter componentsare separated from phenol and the heavier components. The overheadstream 55 is sent to the Lights Topping Tower 112 where light compoundssuch as acetaldehyde are removed as stream 56. The bottoms from thetopping tower, stream 57 are fed to the Refined Acetone Column 113,where product specification acetone is recovered as stream 58. Thebottoms from the Crude Acetone Tower 110, stream 61, comprising phenol,and some AMS, cumene, acetophenone and heavies, is fed to the Heavy EndsTower 114, where the heavy components are separated as stream 63. Theoverhead stream 62 is fed to the Hydrocarbon Removal Tower 115, wherethe residual AMS and cumene are separated from the phenol and pass tothe AMS recovery section as stream 64. The crude phenol product, stream65, is fed to the Phenol Finishing Tower 116, where productspecification phenol is recovered overhead as stream 66. The AMS/cumenestreams 60 and 64 are fed to the AMS Recovery Tower 117 where AMS isrecovered as product stream 69, while cumene as stream 68 is returned tothe oxidizer reactor 101.

[0033] By controlling the split ratios α and β, the amount of AMSproduced in the plant can be continuously set, from about zero to about50 wt.% of the stream containing CHP; preferably from about zero toabout 30 wt.% of the stream containing CHP; more preferably from aboutzero to about 20 wt.% of the stream containing CHP; and most preferablyfrom about zero to about 15 wt.% of the stream containing CHP to meetthe demand of the market for AMS. In addition, propylene oxide, ahigh-valued product, is produced.

[0034] The invention will now be more particularly described withreference to the following Examples. For processing scheme 1, a suitableheterogeneous catalyst is required for use in reactor 103. Examples 1and 3 will describe the synthesis of such a catalyst. Examples 2 and 4will describe the use of these catalysts for reducing CHP to DMPC.

EXAMPLE 1

[0035] A solution containing 500 g of water, 45 g of concentratedphosphoric acid, 117 g of cobalt nitrate and 75 g of concentratedsulfuric acid was prepared with mixing. Another solution was preparedcontaining 1600 g of water and 300 g of aluminum sulfate. These twosolutions were combined with stirring. The molar ratio of thecobalt/aluminum/phosphorous was 1/8/1. The pH of the product wasadjusted to 9 by the addition of a 50 wt.% solution of sulfuric acid.The material was placed in a polypropylene bottle and put in a steam box(100° C.) for 48 hours. The material was then filtered and washed anddried at ˜85° C. A portion of the material was air calcined to 540° C.for six hours. The elemental analyses and physical properties were asshown in Table I. TABLE I Element wt. % Co 7.1 Al 25.3 P 3.4 SurfaceArea, m²/g 145

[0036] A portion of the above material was treated with a 0.1N solutionof ammonium nitrate (100 ml of 0.1N ammonium nitrate solution to 10 g ofcalcined material). This treatment was done a total of four times withfresh solution. The material was then filtered, washed and dried at ˜85°C. A portion of the material was air calcined to 540° C. for six hours.The surface area of this material was 310 m2/g.

EXAMPLE 2

[0037] To a 250-ml round bottom flask fitted with a condenser, stirrerand dropping funnel, and located in a water bath for temperaturecontrol, was charged a mixture of 100.0 g of acetone and 1.00 g of thecatalyst of Example 1. The mixture was heated to reflux (57° C.) withstirring, and 50.0 g of 80 wt.% CHP solution (analyzed as 80.8 wt.% CHP,7.7 wt.% cumene, 6.9 wt.% DMPC, 2.1 wt.% acetophenone) was addeddropwise at an approximate rate of 2 g/min. Following addition of theCHP solution, small samples (˜0.2 ml) of the reactant solution werewithdrawn at regular intervals, filtered, and analyzed by gaschromatograph (GC).

[0038] Table II below shows the composition (wt.%) of the reactantsolution at 1 and 3 hours after the addition of the CHP was complete.For analyzing the data in Table II, the following definitions areprovided:

[0039] CHP Conversion (%)=(wt.% CHP_(feed)−wt.% CHP_(product))/(wt.%CHP_(feed))

[0040] % Increase in DMPC=(wt.% DMPC_(product)−wt.% DMPC_(feed))/(wt.%DMPC_(feed)) TABLE II Feed 1 hr 3 hr Acetone 66.67 66.97 66.72 Cumene2.56 2.41 2.31 Phenol 0.09 0.05 0.06 α-Methyl Styrene 0.07 0.15 0.16Acetophenone 0.70 1.57 1.97 DMPC 2.36 5.95 7.67 Cumene Hydroperoxide26.93 22.53 20.71 CHP Conversion 16.4% 23.1% % Increase in DMPC 152.4%225.2%

[0041] The above example shows that the Co/Al/PO₄ catalyst reduces theCHP to DMPC. The catalyst, being non-acidic, is inactive for thedecomposition of CHP into phenol and acetone.

EXAMPLE 3

[0042] Two hundred and fifty grams of ZrOCl₂.8H₂O and 88 g ofCo(NO₃)₂.6H₂O were dissolved with stirring in 1.5 liters of distilledwater. Another solution containing 130 g of conc. NH₄OH and 1.6 litersof distilled water was prepared. These two solutions were combined atthe rate of 50 ml/min using a nozzle mixing. The pH of the finalcomposite was adjusted to approximately 9 by the addition ofconcentrated ammonium hydroxide. This slurry was then put inpolypropylene bottles and placed in a steambox (100° C.) for 72 hours.The product formed was recovered by filtration, washed with excesswater, and dried overnight at 85° C. A portion of this catalyst wascalcined to 800° C. in flowing air for 3 hours to form a catalyst having20% Co, by weight.

EXAMPLE 4

[0043] To a 250-ml round bottom flask fitted with a condenser, stirrerand dropping funnel, and located in a water bath for temperaturecontrol, was charged a mixture of 100.0 g of acetone and 1.00 g of thecatalyst of Example 3. The mixture was heated to reflux (57° C.) withstirring, and 50.0 g of 80 wt.% CHP solution (analyzed as 80.8 wt.% CHP,7.7 wt.% cumene, 6.9 wt.% DMPC, 2.1 wt.% acetophenone) was addeddropwise at an approximate rate of 2 g/min. Following addition of theCHP solution, small samples (˜0.2 ml) of the reactant solution werewithdrawn at regular intervals, filtered, and analyzed by GC.

[0044] Table III below shows the composition (wt.%) of the reactantsolution at 1 and 3 hours after the addition of the CHP was complete.TABLE III Feed 1 hr 3 hr Acetone 66.67 67.37 67.32 Cumene 2.56 2.27 2.20Phenol 0.09 0.04 0.03 α-Methyl Styrene 0.07 0.13 0.13 Acetophenone 0.702.29 2.43 DMPC 2.36 8.52 9.95 Cumene Hydroperoxide 26.93 19.17 17.48 CHPConversion 28.8% 35.1% % Increase in DMPC 261.2% 321.9%

[0045] The above example shows that a Co/ZrO₂ catalyst reduces the CHPto DMPC. The catalyst, being non-acidic, is inactive for thedecomposition of CHP into phenol and acetone.

EXAMPLE 5

[0046] The catalysts of Examples 1 and 3 are suitable for use in reactor103 of processing scheme 1. By adjusting the split ratio α, and usingthe processing parameters of temperature and contact time to control theconversion, varying percentages of the CHP stream 14 can be reduced toDMPC. For illustrative purposes, a material balance for processingscheme 1 is shown in Table IV where the amount of CHP reduced is variedbetween 0 and about 12%, by weight. TABLE IV % CHP Reduced 0 5 7 11.8Phenol Yield (%) 94.1 88.9 86.8 81.8 AMS Yield (%) 80 171.6 208.2 296.1AMS/Phenol (%) 3.5 8 10 15

[0047] The phenol yield shown in Table IV is the amount of phenolproduced as a percentage of the cumene fed to 101 that is converted. TheAMS yield shown in Table IV is the amount of AMS produced in the plantrelative to the amount of DMPC produced in the oxidation step. As isshown in Table IV, by varying the amount of CHP reduced from zero toabout 12%, the ratio of AMS to phenol produced in the plant can bevaried from 3.5% to about 15%.

[0048] As is known by those skilled in the art, there are many factorsthat influence the yields of a phenol plant. There are many processingsteps in the production of phenol, as illustrated in processing schemes1 and 40, that influence the overall production yields. For illustrativepurposes of this example, the following selectivities have beenpostulated. In the oxidation step, the selectivity of cumene to CHP inreactor 101 is about 95%. The selectivity to DMPC for the non-CHPoxidized products is about 83%. The selectivity in first cleavagereactor 102 and second cleavage reactor 105, to phenol and acetone isabout 99.5%. The selectivity to AMS in the dehydration reaction is about80%. The remaining 20 percent of the AMS is converted to AMS dimers andp-cumylphenol.

[0049] As shown in Table IV, the phenol and AMS yields are a function ofthe CHP that is reduced in the reduction reactor 103. A reduction ofabout 7% of the CHP produced in the oxidation reactor 101 represents anAMS yield relative to the amount of phenol produced by the plant ofabout 10%, representing a yield in excess of 200% which is more thandouble that produced without the use of a reduction reactor.

[0050] The additional DMPC that is produced is independent of the methodby which the CHP is reduced. Consequently, the AMS yields are the sameirrespective of whether the DMPC is formed via a reduction reaction asin the scheme of FIG. 1 or in an epoxidation reaction as shown in thescheme of FIG. 2.

We claim:
 1. A process for producing α-methylstyrene, acetone and phenolcomprising the steps of: (a) oxidizing a stream containing cumene in thepresence of an oxygen-containing stream to form a stream containingcumene hydroperoxide, (b) reacting a portion of said stream containingcumene hydroperoxide in the presence of a catalyst to form a streamcontaining dimethyl phenyl carbinol, and (c) recovering a product streamcontaining α-methylstyrene, acetone and phenol formed by contacting saidstream containing dimethyl phenyl carbinol and the remaining portion ofsaid cumene hydroperoxide stream in the presence of an acidic catalyst.2. The process of claim 1 wherein step (c) includes contacting saidstream containing dimethyl phenyl carbinol, said cumene hydroperoxidestream, and a diluent stream in the presence of said acidic catalyst. 3.The process of claim 2 wherein said diluent stream is acetone.
 4. Theprocess of claim 2 wherein step (c) includes contacting a portion ofsaid product stream with hydrogen in the presence of a hydrogenationcatalyst to form said diluent stream.
 5. The process of claim 1 whereinsaid oxidizing step (a) includes oxidizing said stream containing cumenein the presence of an initiator.
 6. The process of claim 5 wherein saidinitiator is selected from the group consisting of cumene hydroperoxide,tert-butyl hydroperoxide, ethyl benzene hydroperoxide, azo type freeradical initiators, peroxy type free radical initiators, and mixturesthereof.
 7. The process of claim 1 wherein said catalyst of step (b) iscomprised of a metal and a catalyst support.
 8. The process of claim 7wherein said metal is selected from the group consisting of a Group 1metal, a Group 2 metal, a Group 3 metal, a Group 8 transition metal, aGroup 9 transition metal, a Group 10 transition metal, and mixturesthereof.
 9. The process of claim 7 wherein said catalyst support isselected from the group consisting of silica, alumina, crystalline oramorphous aluminophosphates, Group 4 metal oxides, mesoporous molecularsieves, and mixtures thereof.
 10. The process of claim 7 wherein saidmetal is cobalt and said catalyst support is zirconium oxide.
 11. Theprocess of claim 7 wherein said metal is cobalt and said catalystsupport is aluminum phosphate.
 12. The process of claim 1 wherein saidacidic catalyst of step (c) is selected from the group consisting of aliquid catalyst and a solid acid catalyst.
 13. The process of claim 12wherein said liquid catalyst is sulfuric acid.
 14. The process of claim12 wherein said solid acid catalyst is selected from the groupconsisting of a Group 4 metal oxide that has been modified by a Group 6metal oxide, a sulfated transition metal oxide, a mixed metal oxide ofcerium oxide and a Group 4 metal oxide, and mixtures thereof.
 15. Theprocess of claim 14 wherein said solid acid catalyst is contained in afixed bed reactor.
 16. The process of claim 4 wherein said hydrogenationcatalyst is comprised of a hydrogenation component and a catalystsupport.
 17. The process of claim 16 wherein said hydrogenationcomponent is selected from the group consisting of a Group 6 metal, aGroup 7 metal, a Group 8 metal, a Group 9 metal, a Group 10 metal, aGroup 11 metal, and mixtures thereof.
 18. The process of claim 17wherein said Group 10 metal is palladium or platinum.
 19. The process ofclaim 16 wherein said catalyst support is selected from the groupconsisting of alumina, silica, clay, carbon, zirconia, titania,mesoporous molecular sieves, and mixtures thereof.
 20. The process ofclaim 1 wherein said portion of cumene hydroperoxide stream in reactingstep (b) is from about zero up to about 50 weight percent of said streamcontaining cumene hydroperoxide.
 21. The process of claim 20 whereinsaid portion of cumene hydroperoxide stream in reacting step (b) is fromabout zero up to about 15 weight percent of said stream containingcumene hydroperoxide.
 22. A process for producing α-methylstyrene,propylene oxide, acetone, and phenol comprising the steps of: (a)oxidizing a stream containing cumene in the presence of a streamcontaining oxygen to form a stream containing cumene hydroperoxide; (b)reacting a propylene stream and a portion of said cumene hydroperoxidestream in the presence of an epoxidation catalyst to form a streamcontaining dimethyl phenyl carbinol and a first product streamcontaining propylene oxide; (c) recovering a second product streamcontaining α-methylstyrene, acetone, and phenol formed by contactingsaid stream containing dimethyl phenyl carbinol and the remainingportion of said cumene hydroperoxide stream in the presence of an acidiccatalyst.
 23. The process of claim 22 wherein step (c) includescontacting said stream containing dimethyl phenyl carbinol, said cumenehydroperoxide stream, and a diluent stream in the presence of saidacidic catalyst.
 24. The process of claim 23 wherein said diluent streamis acetone.
 25. The process of claim 23 wherein step (c) includescontacting a portion of said product stream with hydrogen and in thepresence of a hydrogenation catalyst.
 26. The process of claim 25wherein said hydrogenation catalyst is comprised of a hydrogenationcomponent and a catalyst support.
 27. The process of claim 26 whereinsaid hydrogenation component is selected from the group consisting of aGroup 6 metal, a Group 7 metal, a Group 8 metal, a Group 9 metal, aGroup 10 metal, a Group 11 metal, and mixtures thereof.
 28. The processof claim 27 wherein said Group 10 metal is palladium or platinum. 29.The process of claim 26 wherein said catalyst support is selected fromthe group consisting of alumina, silica, clay, carbon, zirconia,titania, mesoporous molecular series, and mixtures thereof.
 30. Theprocess of claim 22 wherein said oxidizing step (a) includes oxidizingsaid stream containing cumene in the presence of an initiator.
 31. Theprocess of claim 30 wherein said initiator is selected from the groupconsisting of cumene hydroperoxide, tert-butyl hydroperoxide, ethylbenzene hydroperoxide, azo free radical initiators, peroxy type freeradical initiators, and mixtures thereof.
 32. The process of claim 22wherein said epoxidation catalyst of step (b) is selected from the groupconsisting of titanium supported on silica and titanium supported onmolybdenum.
 33. The process of claim 22 wherein said acidic catalyst ofstep (c) is selected from the group consisting of a liquid catalyst anda solid acid catalyst.
 34. The process of claim 33 wherein said liquidcatalyst is sulfuric acid.
 35. The process of claim 33 wherein saidsolid acid catalyst is selected from the group consisting of a Group 4metal oxide that has been modified by a Group 6 metal oxide, a sulfatedtransition metal oxide, a mixed metal oxide of cerium oxide and a Group4 metal oxide, and mixtures thereof.
 36. The process of claim 35 whereinsaid solid acid catalyst is contained in a fixed bed reactor.
 37. Theprocess of claim 22 wherein said portion of cumene hydroperoxide streamin reacting step (b) is from about zero up to about 50 weight percent ofsaid stream containing cumene hydroperoxide.
 38. The process of claim 37wherein said portion of cumene hydroperoxide stream in reacting step (b)is from about zero up to about 15 weight percent of said streamcontaining cumene hydroperoxide.
 39. A process for producingα-methylstyrene, acetone and phenol comprising the steps of: (a)oxidizing a stream containing cumene in the presence of anoxygen-containing stream to form a stream containing cumenehydroperoxide; (b) recovering a product stream containingα-methylstyrene, acetone and phenol formed by contacting said streamcontaining cumene hydroperoxide and a diluent stream in the presence ofa solid acid catalyst.
 40. The process of claim 39 wherein said diluentstream is formed by contacting a portion of said product stream withhydrogen in the presence of a hydrogenation catalyst.
 41. The process ofclaim 39 wherein at least a portion of said diluent stream is comprisedof acetone.
 42. The process of claim 39 wherein said solid acid catalystis selected from the group consisting of a Group 4 metal oxide that hasbeen modified by a Group 6 metal oxide, a sulfated transition metaloxide, a mixed metal oxide of cerium oxide and a Group 4 metal oxide,and mixtures thereof.
 43. The process of claim 40 wherein saidhydrogenation catalyst is comprised of a hydrogenation component and acatalyst support.
 44. The process of claim 43 wherein said hydrogenationcomponent is selected from the group consisting of a Group 6 metal, aGroup 7 metal, a Group 8 metal, a Group 9 metal, a Group 10 metal, aGroup 11 metal, and mixtures thereof.
 45. The process of claim 44wherein said Group 10 metal is palladium or platinum.
 46. The process ofclaim 43 wherein said catalyst support is selected from the groupconsisting of alumina, silica, clay, carbon, zirconia, titania,mesoporous molecular sieves, and mixtures thereof.
 47. A non-acidiccatalyst for reduction of cumene hydroperoxide to dimethyl phenylcarbinol comprising a metal and a catalyst support.
 48. The catalyst ofclaim 47 wherein said metal is selected from the group consisting of aGroup 1 metal, a Group 2 metal, a Group 3 metal, a Group 8 transitionmetal, a Group 9 transition metal, a Group 10 transition metal, andmixtures thereof.
 49. The catalyst of claim 47 wherein said catalystsupport is selected from the group consisting of silica, alumina,crystalline or amorphous aluminophosphates, Group 4 metal oxides,mesoporous molecular sieves, and mixtures thereof.
 50. The catalyst ofclaim 47 wherein said metal is selected from the group consisting of aGroup 1 metal, a Group 2 metal, a Group 3 metal, a Group 8 transitionmetal, a Group 9 transition metal, a Group 10 transition metal, andmixtures thereof and wherein said catalyst support is selected from thegroup consisting of silica, alumina, crystalline or amorphousaluminophosphates, Group 4 metal oxides, mesoporous molecular sieves,and mixtures thereof.
 51. The catalyst of claim 50 wherein said metal iscobalt and said catalyst support is zirconium oxide.
 52. The catalyst ofclaim 51 wherein said metal is cobalt and said catalyst support isaluminophosphate.